As most people who are not religious say, you do not need religion to have moral standards. I think biology can also offer insight into the right vs. wrong dilemma of life. We each know pain and pleasure and we know that pain is bad while pleasure is good. Morally we can look at each situation and determine who we would bring pain to by acting a certain way and who we would bring pleasure to. If we believe that our actions would bring us and those around us more joy than pain they are good actions, if not they are bad actions.
Of course it gets way more complicated than that in real life but that is the basis, and living within that realm can bring you very, very close to the moral standards of any major religion.